1. Field of the Invention
The present invention relates to a system for conducting communication between two stations, such as a master station and a slave station, by making use of the technique of optical space propagation, and more particularly to a data communication system which inhibits any communication with a device such as a runaway terminal.
2. Description of the Prior Art
FIG. 1 shows the construction of a communication system according to the prior art. This communication system is of the type in which the communication is conducted either between a master station 101 and one of slave stations 102 to 104, or between the slave stations 102 to 104 through the master station 101, by means of optical beams 105 to 107. It is assumed that the slave station 104, for example, runs away during communication with the master station 101 so that it continues the data communication without stopping. In this case, the master station 101 or the slave stations 102 and 103 are unable to conduct any data communication because of the obstruction of the data being sent from the slave station 104.